Simplify the following expression: $t = \dfrac{n}{3} + \dfrac{n}{5}$
Explanation: In order to add expressions, they must have a common denominator. The smallest common denominator is the least common multiple of $3$ and $5$ $\lcm(3, 5) = 15$ $ t = \dfrac{5}{5} \cdot \dfrac{n}{3} + \dfrac{3}{3} \cdot \dfrac{n}{5} $ $t = \dfrac{5n}{15} + \dfrac{3n}{15}$ $t = \dfrac{5n +3n}{15}$ $t = \dfrac{8n}{15}$